The copending patent application of F. S. Emmer and Carl M. Good, Ser. No. 763,231, filed Jan. 27, 1977, describes an immersible molecular filter unit that has a generally cylindrical core with an underdrain structure, about which a semi-permeable membrane is heat sealed. This unit provides a unique combination of easy operation, versatility and low cost to laboratory-scale molecular concentrations and separations. The unit is ideal for concentrating proteins, viruses, and colloids; for removing salts, buffers, and solvents from solutions; for deproteinizing samples; and for separating out unbound ligands.
To use this separator, it is simply immersed in the liquid that is to be processed, and it is then connected through tubing to a source of vacuum. A pre-evacuated, stoppered test tube provides a convenient source of vacuum and a clean receptacle for the collection of filtrate. Atmospheric pressure forces the liquid phase of the material in which the separator is immersed through the membrane. The separations that are achieved depend upon the membrane characteristics.
This unit has been well received. The present invention seeks to improve on that unit with respect to greater ease of testing for integrity, greater ease of manufacture, and superior reliability.